Mattress core



FIG. 1 is a top perspective view of the mattress core;

FIG. 2 is a bottom perspective view;

FIG. 3 is a top view;

FIG. 4 is a bottom view;

FIG. 5 is a side view; and,

FIG. 6 is a front view thereof. 

CLAIM The ornamental design for a mattress core, as shown and described. 